Topical dosage forms are applied to the skin or mucous membranes for local effects. These forms include creams, ointments, gels, and patches. Creams are semi-solid preparations that are easy to apply and are absorbed quickly by the skin. Ointments are thicker than creams and provide a protective barrier on the skin. Gels are clear or semi-solid preparations that are easily spread over the skin. Patches are adhesive strips that deliver medication through the skin over a period of time.